The compound, (E)-4-Dimethylamino-but-2-enoic acid {4-(3-chloro-4-fluorophenylamino)-7-[(S)-(tetrahydro-furan-3-yl)oxy]-quinazolin-6-yl}-amide, known as Afatinib, having the following structure:
is an investigational orally administered irreversible inhibitor of both the epidermal growth factor receptor (EGFR) and human epidermal receptor 2 (HER2) tyrosine kinases. Afatinib is under development for treatment of several solid tumors including non-small cell lung cancer (NSCLC), breast, head and neck cancer, and a variety of other cancers.
Quinazoline derivatives, such as afatinib, are described in WO2002050043. This document also describes certain favourable pharmacological properties of this compound. The dimaleate salt and its crystalline form are described in WO2005037824.
Polymorphism, the occurrence of different crystal forms, is a property of some molecules and molecular complexes. A single molecule may give rise to a variety of polymorphs having distinct crystal structures and physical properties like melting point, thermal behaviors (e.g. measured by thermogravimetric analysis—“TGA”, or differential scanning calorimetry—“DSC”), X-ray powder diffraction (XRPD or powder XRD) pattern, infrared absorption fingerprint, and solid state nuclear magnetic resonance (NMR) spectrum. One or more of these techniques may be used to distinguish different polymorphic forms of a compound.
Discovering new polymorphic forms and solvates of a pharmaceutical product can provide materials having desirable processing properties, such as ease of handling, ease of processing, storage stability, and ease of purification or as desirable intermediate crystal forms that facilitate conversion to other polymorphic forms. New polymorphic forms and solvates of a pharmaceutically useful compound or salts thereof can also provide an opportunity to improve the performance characteristics of a pharmaceutical product. It enlarges the repertoire of materials that a formulation scientist has available for formulation optimization, for example by providing a product with different properties, e.g., better processing or handling characteristics, improved dissolution profile, or improved shelf-life. For at least these reasons, there is a need for additional solid state forms of Afatinib free base and salts thereof.